Do your vacation plans always include a beautiful island? Here are three incredible destinations to eat fresh seafood, learn how to salsa dance, and climb over huge boulders—plus one little paradise you can only dream about . . . for now.

Southport: Ride a Navy motor whaleboat, eat lobsters and steamers, and watch the fog roll out to sea at your own lighthouse before it gets too cold off the coast of Maine.

Old San Juan: Step back in time by sleeping in an old convent, exploring forts and churches, and learning how to salsa dance in Puerto Rico.

The Baths: Climb over huge boulders, float in echoey caves, and wade through tidal pools in one of the most beautiful spots in the Caribbean.

Diego Garcia: Imagine an off-limits island in the Chagos Archipelago, where warrior crabs rule the jungle, hawksbill sea turtles lay their eggs on empty beaches, and lagoons are full of enormous rays.